SUMMARY

Using new collecting techniques with the Johnson-Sea-Link submersible, eight species of deep-sea benthic crustaceans were collected with intact visual systems. Their spectral sensitivities and temporal resolutions were determined shipboard using electroretinography. Useable spectral sensitivity data were obtained from seven species, and in the dark-adapted eyes, the spectral sensitivity peaks were in the blue region of the visible spectrum, ranging from 470 to 497 nm. Under blue chromatic adaptation, a secondary sensitivity peak in the UV portion of the spectrum appeared for two species of anomuran crabs: Eumunida picta (λmax 363 nm) and Gastroptychus spinifer (λmax 383 nm). Wavelength-specific differences in response waveforms under blue chromatic adaptation in these two species suggest that two populations of photoreceptor cells are present. Temporal resolution was determined in all eight species using the maximum critical flicker frequency (CFFmax). The CFFmax for the isopod Booralana tricarinata of 4 Hz proved to be the lowest ever measured using this technique, and suggests that this species is not able to track even slow-moving prey. Both the putative dual visual pigment system in the crabs and the extremely slow eye of the isopod may be adaptations for seeing bioluminescence in the benthic environment.

FOOTNOTES

FUNDING

Funding for this research was provided by the National Oceanographic and Atmospheric Administration, Office of Ocean Exploration [NA050AR4601059 to T.M.F. et al., NA07OAR46000289 to S.J. et al. and NA09OAR4600095 to T.M.F. et al.]. S.J. was also supported in part by grants from the National Science Foundation [OCE-0852138 to S.J. et al.] and the Office of Naval Research [N00014-09-1-1053 to S.J. et al.]. T.W.C. was supported in part by grants from the National Science Foundation [IOS-0721608 to T.W.C. et al.] and the Air Force Office of Scientific Research [FA9550-09-1-0149 to T.W.C.].